The present invention relates to a Y-type cylinder-controlled valve assembly, and more particularly to a valve assembly in which cylinder and piston are used to control the travel and stop of the valve thereof. The specially designed valve body facilitates the smooth open and close of the valve and prevents the valve from being easily stuck in the valve body.
In a conventional cylinder-controlled valve, the fluid in the valve body flows in a direction normal to the direction of displacement of the piston to open or close the valve, and is therefore forced to wind its way in the valve body. This reversely disturbs and drops the flow while causes pressure drop.
To solve this problem, the Y-type cylinder-controlled valve assembly has been developed. The Y-type cylinder-controlled valve assembly is characterized in the almost straight flow passage in the valve body and that the valve controlling the open and close of the valve body moves in a direction at an angle of 50 degrees from the flow passage. With this design, the fluid in the valve body would not be stopped and disturbed while the problem of pressure drop can be improved.
FIG. 1 illustrates a conventional Y-type cylinder-controlled valve assembly, in which a valve body 91 has an internal valve 92 whose top is provided with an inclined shoulder 93. A seal ring 95 can be fixed into a recess formed at the bottom side of the valve 92 by means of a washer 94. With this structure, the control valve may conveniently and effectively prevent any leakage of fluid from the valve as well as reduce the back pressure of the valve to facilitate the instant open of valve body.
In the above described conventional Y-type cylinder-controlled valve assembly, when the valve body is opened, the valve 92 shall keep rising until it moves into a cavity formed at the bottom end of a coupling sleeve 96. That is, the valve 92 is stopped when its top surface contacts the bottom cavity of the coupling sleeve 96 and therefore, the valve 92 has to bear considerably large force at this point. And, as shown in FIG. 1.1, the clearance left between the valve 92 and the valve body wall 97 is so small that the valve 92 is easily stuck in the valve body 91 whenever the valve 92 is biased under the fluid pressure and contacts the slant side wall 97 of the valve body 91.
Another disadvantage existed in the conventional Y-type cylinder-controlled valve assembly is that no protective means is provided over top end of the indicator 99 inside the cylinder 98. Dust and moistures may easily enter the cylinder 98 from the top end of the indicator 99 and damage the piston. Since the Y-type cylinder-controlled valve assembly is frequently used in a severe environment, the invasion of any foreign material into the cylinder shall be specially noted and avoided.
Moreover, the valve 92 inclinedly extends into the fluid passage at an angle of 50 degrees in the direction of fluid flow, forming a much shorter distance between the cylinder 98 and the pipe connected to and extending from the fluid inlet of the valve body 91, which reversely influences the convenience in connecting the pipe. When a flange is used in such pipe connection, such Y-type valve assembly with 50-degree inclined valve is difficult to meet the JIS specification.